<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>test</title>

  <style>
.flexbox {
    display: grid;
    grid-template-rows:repeat(2,150px);
    grid-auto-flow: column; 
    column-gap:1rem;
    row-gap:10px;
}

.flex-item {   
    flex-basis: 280px;
    flex-shrink:none;
    height: 150px;
    background:red;
    margin-right:10px;
    margin-bottom:10px;
}
  </style>
</head>

<body>
  <div class="flexbox">
    <div class="flex-item"></div>
    <div class="flex-item"></div>
    <div class="flex-item"></div>
    <div class="flex-item"></div>
    <div class="flex-item"></div>
    <div class="flex-item"></div>
    <div class="flex-item"></div>
    <div class="flex-item"></div>
    <div class="flex-item"></div>
  </div>

  <script>
    
  </script>

</body>

</html>